CLAD MIG WELD BEST PRACTICE..
Written by E Craig. www.weldreality.com.
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When employees lack MIG weld process control - best weld practice expertise, the weld shops are simply throwing money out of the window, and in the power station water wall clad application (below), they are dramatically adding to the weld costs and shortening the life of the water wall boilers.
With clad weld consumables that can cost from $7 to $30 a pound,I
hope your company does not make Inconel or Stainless.
MIG clad welds that look like those below.
Cladd Repairs on Boiler Water Walls.
Sad MIG cladd weld procedure, using a poor power source and poor weld practices.
Above: This water wall MIG clad
application photo was proudly displayed in a weld magazine:
The magazine article on boiler wall clad welding was about a new, 2008 pulsed MIG power source available from
Miller Electric, and the suitability of this equipment to this complex, Inconel clad application.
The clad welds in the photo reveal poor pulsed MIG transfer weld characteristics, poor settings, a poor pulsed MIG program for the alloys,
and poor clad weld practices and techniques.
as above will create inconsistent, unnecessary weld over lap, poor and excess weld at the clad
tie-ins and welds that would have poor, inconsistent fusion and clad dilution. Also the excess weld start stops did not help. A clad weld operation such as this can dramatically negatively effect the boiler walls by producing excess distortion, uneven
wear, unnecessary stresses and stress risers, weld issues that can reduce the boiler operation efficiency
Ed's untouched, single pass MIG Clad Welds on Water Wall tubes.
622 on Boiler Water Walls. An untouched weld section take from 3000 sq/ft clad section.
Ed's contribution to the
Global Power and
Waste Management Industries.
Welding Services (WSI) now Aquilex Atlanta: WSI is primarily involved in repairs and refurbishment
in the power, waste energy and nuclear industries. In terms of water wall
welding, WSI has clad approx. 80% of the North American boilers. Each year
WSI uses approx.
one million pounds of Inconel 625-622 and 300 series stainless
MIG wires for cladding boiler
water wall tubes.
2006: I WAS REQUESTED TO DEVELOP
A NEW WATER WALL CLAD PATENT:
While WSI (Aquilex) has produced some of the most innovative, automatic
MIG cladding equipment available in North America, WSI did not have a resident
MIG process control expert who had the process control - best practice expertise necessary to make radical improvements
to it's water wall clad MIG welds.
I was contracted for this work by the WSI
engineering manager. In less than 6 months, as the following pictures indicate, I dramatically improved the single pass water wall overlay weld quality and a new USA and
European clad weld patent was developed.
WITH ALL CLAD WELDS, THE MOST DESIRABLE CLAD WELD ATTRIBUTE IS ACHIEVE THE LEAST POSSIBLE WELD LESS DILUTION:
IMPROVING WATER WALL
BOILER LIFE & OPERATING EFFICIENCY:
many in the power industry are aware, with any water wall clad weld application "less
is always better". With less clad weld shrinkage and less clad weld defects, the boiler water walls will operate more efficiently when the single pass
clad weld surface is as thin as possible and when the clad weld pass thickness is both uniform and free
of weld defects.
The traditional methods of both manual and automated clad welds on boilers would produce clad welds similar to the macro picture on the left. In most cases too much MIG weld filler would be applied.
The automated MIG clad welds which should have the best controls of the welds would also typically look poor, lack consistency, lack uniformity and have poor weld tie ins. These alloy welds would also have extensive lack of fusion.
Inconel clad filler metals typically can cost over $20 - $30 a pound. With these costly MIG weld wires, it makes no sense to produce excess weld and create weld heat and excess stresses and deformation on the boiler walls. In contrast, my new clad patent dramatically
pass clad weld quality, and dramatically
reduced the typical
single pass clad weld thickness. These single pass welds also provided superior chemistry. and the bottom line also provided extensive clad cost savings from the reduced weld wire and rework requirements:
REDUCTIONS IN CONSUMABLE WELD COSTS PER-OPERATION.
With Inconel clad wires at $20 - $30 a pound and large water wall / vessel tank or pipe areas to be clad, the clad weld consumable
costs can typically be a large part of the cost of a clad application costs. My new pulsed MIG procedures - practices reduced the amount of clad single pass, clad
weld overlay by approx. 28%.
PASS CLAD WELDS, YOU HAVE UNIQUE WELD REQUIREMENTS FOR THE CLAD WELD SURFACE TIE-INS AND FOR THE CLAD TO TUBE WHICH REQUIRES MINIMUM CLAD WELD DILUTION:
water wall clad applications, the minimum, "single pass" Inconel weld
clad chemistry required is 20% chrome. As the filler metal typically provides approx 21% chrome To attain the minimum chrome requirements,
the pulsed MIG weld procedures with the vertical down clad welds consistently
attained minimum weld dilution < 8%, while achieving consistent weld fusion
on the carbon steel boiler tubes.
BOILER SHUT DOWN IS COSTLY AND WELD TIME IS VERY IMPORTANT WHEN CLADDING LARGE WATER WALL AREAS THAT SOMETIMES REQUIRE OVER 1000 sq/ft OF CLADDING. TO SPEED UP THE OPERATION, THE CLAD PROCESS NEEDS TO PRODUCE THE HIGHEST POSSIBLE WELD DEPOSITION RATES:
primary part of clad weld costs on large weld areas as found with most clad boiler
wall applications, is dictated by
weld deposition rates attained. My patented clad procedure with
the unique, WSI automated weld equipment, enabled a single operator controlling
two guns to deposit approx. 30 lbs/hr.
Weld spatter with any MIG weld mode is an indication of
LACK OF MIG WELD PROCESS CONTROL EXPERTISE
2006: My patented pulsed MIG weld operation on the left. This gun was providing 15 - 16 lb/hr with the lowest possible single pass pass weld dilution. Note the absense of weld spatter at a time period (10 years ago) when the pulsed MIG technology was and still is in many instances a joke..Compare with the so called normal water wall pulsed MIG clad welds on the right:
you sell the costly stainless or Nickel clad weld consumables,
clad boiler welds, LESS IS BEST.
Left above: My "single pass" clad welds provided
dilution so low that the
stainless chrome content was always > 20%.
I got involved with boiler water wall welds, the picture below was considered by WSI to be an
optimum, Inconel 622,
Vertical Down, automated Pulsed MIG, water wall, clad application.
Below, My untouched, single pass
patented stainless / inconel weld showing obvious MIG clad weld quality
Note my smooth single layer MIG clad surface with optimum weld blend ties ins. This
clad application was delivered from a low cost, $5000 pulsed MIG power source
in 2006. This pulsed MIG clad weld has a smooth finish similar to a $250.000 laser - powder
clad overlay. In contrast to the conventional water wall clad MIG welds, and in contrast to what WSI had been producing for decades, Ed's pulsed MIG process
change required 28 % less weld metal per sq/ft of coverage. These single pass, low dilution welds also provided > 20 % chrome.
I developed the best posasible MIG gas mix for stainless and inconel alloys.
UNIQUE INCONEL CLAD MIG GAS
MIX WAS DEVELOPED BY ED
vertical down 622 Inconel / stainless clad MIG welds in Ed's patent were derived from a low cost,
five thousand dollar, pulsed MIG power source and a unique Inconel MIG gas
mix that was also developed by Ed. (See the MIG gas data section at this site).
Note: This patent would not have been possible without the Aquliex, (WSI), customized. automated MIG weld equipment that compensated
for the wire stick
out and arc length variations that resulted from the water wall curves.
MY CLAD PROCEDURE BECAME THE PATENT
a few months of pulsed MIG weld process development.
The final Inconel 622,
single pass, clad
weld results were developed by Ed for WSI, (Aquilex).
In 2010 an International - USA patent on cladding was presented to Ed and WSI.
ELECTRO - SLAG WHY BOTHER?
ON LARGE SCALE POWER PLANT WELD APPLICATIONS, I DID A COST - QUALITY ANALYSIS OF ELECTRO SLAG WELDS (ESW) versus MIG FOR THE WORLD'S LARGEST CLADIING COMPANY.
WITH THE MIG PROCESS CONTROLS - BEST PRACTICES THAT I PROVIDED. I PRODUCED SUPERIOR MIG CLAD QUALITY AT LOWER COSTS THAN THE ESW SYSTEMS COULD PROVIDE.
THE MIG CLAD DILUTION IN MY 30 POUND / HR - PER HR. TWIN TORCH OPERATION RESULTED IN SINGLE PASS CLAD MIG WELDS WITH < 5% Fe AND > 20% CHROME.
COSTLY MIG EQUIPMENT WAS NOT NECESSARY:
BY THE WAY IT'S NOT NECESSARY TO PURCHASE A HIGH COST FRONIUS OR ANY OTHER HIGH COST ELECTRONIC MIG UNIT TO ACHIEVE THE CLAD RESULTS.
USA / European MIG patent that I generated for single pass clad welds used on boiler water walls, tanks, vessels, pipe or valves, I used a pulsed MIG MIG power source that cost approx. $6000.
See ESW versus MIG below.
2015: Note: You are wasting money if you spend more than $7000 on a power source for any MIG clad application.
The the best process for clad welding when the highest weld quality is required is not a Hot or Cold Wire TIG process, it's the far superior TIP TIG process. This is a process that I introduced to North America and Australia. Visit the TIP TIG section at this site.
Follow up eight years later in 2014:
From Ankit Jindal, Welding engineer, M/s ISGEC HEAVY ENGINEERING LTD, INDIA.
Ed, I just viewed the pictures of your pulsed MIG cladding technique with inconel 625 over carbon steel water wall tubes. My company is a major boiler manufacturer here in india and we have installed more than 550 power boilers in more than 30 countries.
We will be working on a project where we will be cladding INCONEL 625 over water wall panel tubes. Initially we thought of doing it with manual pulsed arc MIG, vertical down by hand, but after viewing your superb finish and minimum dilution method, I couldn’t resist to write it to you. We are very much impressed with your MIG process control expertise and your pioneer knowledge of the subject. We will be very much grateful, if you’ll be able to spare some time to chat with us.
Ed also provided unique MIG Water Wall Clad Welds in the 1980's.
the 1980s, twenty years before the development of decent pulsed MIG equipment, Ed produced the Inconel
622 MIG clad weld shown in the left photo (cross section of a boiler tube). In
his clad weld there was no metallurgical evidence of a heat affected zone as evidence
in the macro.
In contrast on the right photo we have the typical MIG clad
weld fusion profiles
that the power industry and it's water wall boilers were accustomed to in 1980 and in 2008.
Inconel clad weld shown on the LEFT macro was made
by Ed and his buddy Zugy without any cooling medium and made
MIG power source and process developed in 1963. The weld on the right is the usual poor quality MIG cladd weld with too much weld dilution. Notice on Ed's weld (left) the desired minimum cladd dilution and the lack of a visable HAZ with the unique MIG process utilized.
and my unique Controlled Short Circuit Clad Weld made 1983.
All thats required is process control expertise.
622 MIG Cladd... I doubt few companies with their twenty first Century, sophisticated, electronic MIG equipment could achieve a clad weld of this weld quality without a visable heat affected zone. My macro even surprised the Foster
Wheeler senior metallurgist who examined it, as their was no evidence of any 622 alloy weld
dilution with the carbon steel base alloy, and also little evidence of the clad weld HAZ.
It would be a waste of your time to try and produce these welds.
WITHOUT MIG EQUIPMENT BELLS AND WHISTLES, IN THE 1980s, MY BUDDY ZUGY AND I PRODUCED SOME REMARKABLE ALLOY WELDED PARTS:
never had MIG electronic equipment bells and whistles in the 1980s, yet we did have weld
process expertise and low cost MIG weld equipment that was developed in the 1960s. In those
days we were producing welds that are still are not produced 30 years later. In
1980 if you wanted a small vessel made from aluminum bronze you ordered a solid
bar stock and spent many hours ID and OD machining, or you had it cast at a foundry
and waited 6 months to a year. Of course you could have or called me and I would show you how with a few pounds on Alum Bronze 0.045 MIG weld wire,
in a few hours you could make the part strictly out of weld metal as shown on the left.
If you needed
a small vessel comprised of two different alloys such as the machined piece show above middle, With this part the customer want one half made out of Hastelloy and the other half made out of 316 stainless. With the Hastelloy - Stainless part, you could have
spent weeks figuring out how to make it and a small fortune in machining, or you
could have called myself or Zugy and in less than a day the product would have been
made from Hastelloy and stainless MIG weld wire. Yes of course these parts would pass any X-Ray evaluation.
Of course if you really wanted to impress someone in the 1980s you woul produce the
holy grail of welding. Ed and Zugy took some scrap Titanium weld wire, and
in three hours made the above chalice (right) a part yet again free of defects.
and Hydro-Processing Vessels
347 Another common global clad application
overlay application influenced by Ed:
Electro Slag Strip Electrode Process applying ER 347 clad welds.
Above a common Electro Slag Weld common Application. In
the refinery industry, pressure vessels used in high temperature, high pressure
"hydrogen service" such as hydrocracking and hydrotreating are usually
constructed of Chrome / Molly or Vanadium modified Chrome / Moly steels. To overcome
corrosion areas with these vessels, clad welds of ER 347 alloy are typically applied
to plate or to wasted
areas on pressure vessels.
The most common, global cladding "process"
utilized for plate cladding used for hydrogen service, has been the Electro Slag
Welding (ESW). This process uses strip electrodes two to three inches wide. On
some applications a butter layer of ER 309 is requested followed by a surface
layer of ER 347 for the clad surface. On other applications a single layer of
ER 347 is applied.
the ESW process, high deposition welds result from weld current > 600 amps.
The ESW process has been considered unique in that the large size of the strip
electrode results in low weld current density resulting in "low weld dilution".
The down side of th ESW clad process is;
The ESW is a "single" electrode process,
[b] ESW requires a large equipment package, it's cumbersome
and weld position restricted,
[c] the cost of the ESW clad consumables and
fluxes are high,
[d] there are few companies with ESW expertise.
American vessels are ESW clad in Japan.
a unique MIG weld wire found by Ed, and cladding equipment developed by WSI, Ed produced "single pass", MIG layer clad 347 welds
that met the hydrogen service 347 clad thickness, chemistry and ferrite requirements.
In comparison to the ESW and SAW process, thanks to the large differences in consumable
costs and the multi MIG gun capability, it's now possible in contrast to the ESW process to produce the 347 MIG
clad welds, depending on the application with a 30 to 50% cost reduction.
contrast to the much more costly ESW and SAW processes, the single pass MIG clad
procedure developed by Ed and WSI enables cladding on a much wider range of applications,
and allows the flexibility to provide the vessel cladding at any site locations with the vessel in any position.
This weld flexability dramatically reduces the vessel lead times or shipping costs to have this
clad work done.
MIG PROCESS CONTROL EXPERTISE CHANGED THIS TRADITIONAL
GLOBAL 347 ELECTRO
SLAG AND SAW WELD CLAD APPLICATION.
From ESW to Ed's 347 single pass MIG clad weld.
a clad MIG process that's faster, provides less distortion,
has less heat
effect on the steel, costs less and is much more versatile.
in 2015, with some pulsed MIG equipment,
we can now attain what
we were doing with weld process expertise in the 1980s.
you have a clad welding challenges on those ID-OD power plant, refinery, and well
head equipment such as ID welds on adapter flanges,bonnets, studded tees, tree
caps, weld neck flanges, gate valves, please note, you can invest hundreds of
thousands of dollars in sophisticated overlay equipment and never quite get that
application the way it could be. You could ask a salesman for your pulsed clad
MIG advice, or you could learn how to control this important process
and produce clad welds without weld rework.
helps to have weld control process expertise.
Without question a great process for the highest quality - lowest weld heat clad welds
is from a process my business partner and I bought to the USA and Aus.
Visit the TIP TIG section of this site
Russia's solution to mfg. and their
poor quality auto - truck engine problems.
Is this a
one horse car engine? Remember if you dont have a sense of humor
and you are in the welding industry, you made a poor career choice.
Your keys to MIG weld process optimization: